Tungsten heavy alloy sheet can be produced by rolling sintered slabs of the alloy. Because the rolling requires numerous anneals it is desirable that the starting slab be no more than about twice the final thickness. One method to produce these slabs is by isostatically pressing the powder alloy blends and sintering them to full density. With thin slabs it is difficult to get a uniform fill of the mold so the resulting slabs are not uniform in thickness. There is also a problem with breakage with the thin slabs. Using this method, it is not possible to produce slabs with a surface area to thickness ratio much over 600 or thickness less than about 0.5".
Another method of making tungsten heavy alloy sheet is to press large billets and cut the green billet into thin slabs. While this process produces slabs of uniform thickness it has the size limitations of the previous method and there is the added expense of cutting.
It would be desirable to make a sheet preform substantially close in thickness to the final thickness of the rolled sheet. This would reduce the time, energy, and labor required for hot rolling and annealing.
U.S. Pat. Nos. 3,909,241 and 3,974,245 relate to free flowing powders which are produced by feeding agglomerates through a high temperature plasma reactor to cause at least partial melting of the particles and collecting the particles in a cooling chamber containing a protective gaseous atmosphere where the particles are solidified. In this patent, the powders are used for plasma coating and the agglomerated raw materials are produced from slurries of metal powders and binders.